An important function of the rodent primary somatic sensory cortex (Sml) is to integrate information arising from temporally and spatially patterned deflections of the mystacial vibrissae. An emerging model of this sensory cortex is that it is comprised of 25-30 individual columns, each of which is related principally to a single mystacial vibrissa and each of which contains a central core surrounded by integrative multi-whisker zones where individual columns interface. The purpose of this project is to examine in detail the functional organization and intrinsic connectivity of one of these columns. Neurophysiological techniques will be used to study how individual neurons integrate complicated sensory stimuli produced by an array of independently controllable whisker stimulators. A variety of anatomical techniques will be used to determine a structural counterpart to the interactions among cortical columns revealed by the physiological data. In some experiments intracellular recording and labeling of single neurons will provide a direct correlation between morphological and functional data at the cellular level. The proposed research will thus establish how individual cortical columns operate as basic functional modules underlying cortical information processing. In the long term such knowledge will provide an experimental basis for the clinical diagnosis and treatment of sensory dysfunction and cognitive impairment.